libstdc++-v3/include/ext/alloc_traits.h

   1 // Allocator traits -*- C++ -*-
   2
   3 // Copyright (C) 2011-2022 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /** @file ext/alloc_traits.h
  26  *  This file is a GNU extension to the Standard C++ Library.
  27  */
  28
  29 #ifndef _EXT_ALLOC_TRAITS_H
  30 #define _EXT_ALLOC_TRAITS_H 1
  31
  32 #pragma GCC system_header
  33
  34 # include <bits/alloc_traits.h>
  35
  36 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
  37 {
  38 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  39
  40 /**
  41  * @brief  Uniform interface to C++98 and C++11 allocators.
  42  * @ingroup allocators
  43 */
  44 template<typename _Alloc, typename = typename _Alloc::value_type>
  45   struct __alloc_traits
  46 #if __cplusplus >= 201103L
  47   : std::allocator_traits<_Alloc>
  48 #endif
  49   {
  50     typedef _Alloc allocator_type;
  51 #if __cplusplus >= 201103L
  52     typedef std::allocator_traits<_Alloc>           _Base_type;
  53     typedef typename _Base_type::value_type         value_type;
  54     typedef typename _Base_type::pointer            pointer;
  55     typedef typename _Base_type::const_pointer      const_pointer;
  56     typedef typename _Base_type::size_type          size_type;
  57     typedef typename _Base_type::difference_type    difference_type;
  58     // C++11 allocators do not define reference or const_reference
  59     typedef value_type&                             reference;
  60     typedef const value_type&                       const_reference;
  61     using _Base_type::allocate;
  62     using _Base_type::deallocate;
  63     using _Base_type::construct;
  64     using _Base_type::destroy;
  65     using _Base_type::max_size;
  66
  67   private:
  68     template<typename _Ptr>
  69       using __is_custom_pointer
  70         = std::__and_<std::is_same<pointer, _Ptr>,
  71                       std::__not_<std::is_pointer<_Ptr>>>;
  72
  73   public:
  74     // overload construct for non-standard pointer types
  75     template<typename _Ptr, typename... _Args>
  76       [[__gnu__::__always_inline__]]
  77       static _GLIBCXX14_CONSTEXPR
  78       std::__enable_if_t<__is_custom_pointer<_Ptr>::value>
  79       construct(_Alloc& __a, _Ptr __p, _Args&&... __args)
  80       noexcept(noexcept(_Base_type::construct(__a, std::__to_address(__p),
  81                                               std::forward<_Args>(__args)...)))
  82       {
  83         _Base_type::construct(__a, std::__to_address(__p),
  84                               std::forward<_Args>(__args)...);
  85       }
  86
  87     // overload destroy for non-standard pointer types
  88     template<typename _Ptr>
  89       [[__gnu__::__always_inline__]]
  90       static _GLIBCXX14_CONSTEXPR
  91       std::__enable_if_t<__is_custom_pointer<_Ptr>::value>
  92       destroy(_Alloc& __a, _Ptr __p)
  93       noexcept(noexcept(_Base_type::destroy(__a, std::__to_address(__p))))
  94       { _Base_type::destroy(__a, std::__to_address(__p)); }
  95
  96     [[__gnu__::__always_inline__]]
  97     static constexpr _Alloc _S_select_on_copy(const _Alloc& __a)
  98     { return _Base_type::select_on_container_copy_construction(__a); }
  99
 100     [[__gnu__::__always_inline__]]
 101     static _GLIBCXX14_CONSTEXPR void _S_on_swap(_Alloc& __a, _Alloc& __b)
 102     { std::__alloc_on_swap(__a, __b); }
 103
 104     [[__gnu__::__always_inline__]]
 105     static constexpr bool _S_propagate_on_copy_assign()
 106     { return _Base_type::propagate_on_container_copy_assignment::value; }
 107
 108     [[__gnu__::__always_inline__]]
 109     static constexpr bool _S_propagate_on_move_assign()
 110     { return _Base_type::propagate_on_container_move_assignment::value; }
 111
 112     [[__gnu__::__always_inline__]]
 113     static constexpr bool _S_propagate_on_swap()
 114     { return _Base_type::propagate_on_container_swap::value; }
 115
 116     [[__gnu__::__always_inline__]]
 117     static constexpr bool _S_always_equal()
 118     { return _Base_type::is_always_equal::value; }
 119
 120     __attribute__((__always_inline__))
 121     static constexpr bool _S_nothrow_move()
 122     { return _S_propagate_on_move_assign() || _S_always_equal(); }
 123
 124     template<typename _Tp>
 125       struct rebind
 126       { typedef typename _Base_type::template rebind_alloc<_Tp> other; };
 127 #else // ! C++11
 128
 129     typedef typename _Alloc::pointer                pointer;
 130     typedef typename _Alloc::const_pointer          const_pointer;
 131     typedef typename _Alloc::value_type             value_type;
 132     typedef typename _Alloc::reference              reference;
 133     typedef typename _Alloc::const_reference        const_reference;
 134     typedef typename _Alloc::size_type              size_type;
 135     typedef typename _Alloc::difference_type        difference_type;
 136
 137     __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
 138     static pointer
 139     allocate(_Alloc& __a, size_type __n)
 140     { return __a.allocate(__n); }
 141
 142     template<typename _Hint>
 143       __attribute__((__always_inline__)) _GLIBCXX_NODISCARD
 144       static pointer
 145       allocate(_Alloc& __a, size_type __n, _Hint __hint)
 146       { return __a.allocate(__n, __hint); }
 147
 148     __attribute__((__always_inline__))
 149     static void deallocate(_Alloc& __a, pointer __p, size_type __n)
 150     { __a.deallocate(__p, __n); }
 151
 152     template<typename _Tp>
 153       __attribute__((__always_inline__))
 154       static void construct(_Alloc& __a, pointer __p, const _Tp& __arg)
 155       { __a.construct(__p, __arg); }
 156
 157     __attribute__((__always_inline__))
 158     static void destroy(_Alloc& __a, pointer __p)
 159     { __a.destroy(__p); }
 160
 161     __attribute__((__always_inline__))
 162     static size_type max_size(const _Alloc& __a)
 163     { return __a.max_size(); }
 164
 165     __attribute__((__always_inline__))
 166     static const _Alloc& _S_select_on_copy(const _Alloc& __a) { return __a; }
 167
 168     __attribute__((__always_inline__))
 169     static void _S_on_swap(_Alloc& __a, _Alloc& __b)
 170     {
 171       // _GLIBCXX_RESOLVE_LIB_DEFECTS
 172       // 431. Swapping containers with unequal allocators.
 173       std::__alloc_swap<_Alloc>::_S_do_it(__a, __b);
 174     }
 175
 176     template<typename _Tp>
 177       struct rebind
 178       { typedef typename _Alloc::template rebind<_Tp>::other other; };
 179 #endif // C++11
 180   };
 181
 182 _GLIBCXX_END_NAMESPACE_VERSION
 183 } // namespace __gnu_cxx
 184
 185 #endif